The 137th version of this competition will also be the first final between these clubs in a decade and means the domestic season has a fixture to relish just when it seemed to be petering out.

Antonio Conte, manager of Chelsea makes a point. Photo: Getty Images

"We are talking about two managers with strong characters, and two winners. When in your mind and your heart and your blood there is the will to win. For sure, we want to try to win this trophy," declared Antonio Conte after his team's victory.

To try? Conte will be desperate to win. It is, as he said, in his "blood".

And he will be desperate to get one over on Mourinho, despite claiming their strained relationship had been repaired, making it all the more delicious that they are in each other's way back at Wembley on May 19 for a match universally expected to be the Italian's last as Chelsea head coach.

How Conte, like Mourinho, a manager sated only by claiming silverware, would delight in denying his rival.

Charlie Austin of Southampton shoots and misses. Photo: Getty Images

How he will fear being denied by him also, especially with that accusation hanging over him that, despite his impressive record of winning leagues, he often falls short in cup competitions.

That happened again last season, when Arsenal improbably denied Chelsea a Premier League and FA Cup double with Giroud among their ranks, and there was a sweet vindication for Conte in selecting his £18m January signing, and Wembley specialist, ahead of Alvaro Morata.

Chelsea's record acquisition, who eventually replaced Giroud, also scored, with his first touch, to make Conte's selections all the more sound.

Southampton did not show any ambition until they fell behind and there was a moment of controversy over whether they should have been awarded an equalising goal as Chelsea goalkeeper Willy Caballero, under pressure from Charlie Austin, fumbled the ball over his goal-line.

Inevitably, referee Martin Atkinson gave a foul, but Southampton manager Mark Hughes was furious and may well have had a case.

"It was a match-defining moment," he said. "Who knows how the game might have followed from that moment? Why it wasn't referred (to the video assistant referee), I have no idea. We're disappointed with the officials and whoever it is who sits in a darkened room."

Is it a darkened room? Either way, it is looking bleak for Southampton, who may no longer be in this competition but who now have four cup finals of their own as they desperately fight against the probability of relegation from the Premier League.

The deadlock was finally broken after a first period in which Chelsea dominated and Willian came closest as he clipped the top of the crossbar just 28 seconds into the second-half.

It was, as the cliche goes, a goal to grace the occasion. It was also, as another cliche states, an example of good feet for a big man.

It came as Cesc Fabregas flighted the ball forward and Eden Hazard - who pipped Giroud as Man of the Match - acrobatically pulled the ball down and delivered it into the striker's path.

Even though he was inside the penalty area, Giroud had much to do, but showed incredible balance and nimbleness to first beat Mario Lemina, as he lunged in, then Maya Yoshida, then Cedric Soares, before finally poking his shot into the net as Jan Bednarek tried to block.

In doing so, the defender collided with goalkeeper Alex McCarthy and, as Southampton bodies were forlornly strewn in Giroud's path, there were shades of Ricky Villa's Cup final goal for Tottenham Hotspur against Manchester City in the 1980s.

"My second passion is skiing!" Giroud said of his slalom run.

"I saw a lot of people in front of me and I just tried to dribble a little bit and I had a bit of luck, but that's what I wanted to do. I told them I really enjoy the FA Cup as I know how special it is to win it. It (Wembley) is like my garden and I love to play here."

The 31-year-old has not lost in 10 appearances at Wembley - four FA Cup semi-finals, three finals (for Arsenal in 2014, 2015 and 2017, meaning he could win it four times in five years) and three Community Shields.

That is a remarkable record and it would be surprising if Conte did not keep faith with Giroud for the final.

Beyond the Caballero incident, Southampton had another chance to equalise when Austin, their best player, cleverly dummied to release Shane Long, whose touch was far too heavy and, although he went past the goalkeeper, he also ran the ball out of play.

Then Morata came on and added a second goal from a combination that has served Chelsea so well this season: a cross from Cesar Azpilicueta on the right, with his fellow Spaniard rising high to guide a header into the goal.